BIOLOGY LEARNING MATERIALS

CYTOLOGY

Is the study of cells structures and their functions

A cell is an organized independent mass of protoplasm (nucleus and cytoplasm) which makes the basic primary structure of an organism.

CELL CONCEPT:

One of the most important concept in biology is that a cell is a basic structural and functional unit of living organism.

This is known as a cell theory and was proposed jointly by two scientists . A Belgian Botanist called Schleiden and the German zoologist called Schwan. They studied the plant cell and animal cell respectively and come up with the idea that plants and animals are made up by small individuals which perform different functions of the whole organism. They finally come up with what they say cell theory.

The cell theory embraces four ideas, these are:

1. Living organisms are made up of smallest sufficient unit of living matter called cell.
2. The new cell is derived from pre-existing ones by cell division.
3. Each cell is independent with others but function as integral part of the whole organism.
4. The cell contains the hereditary material which is passed from generation to generation.

TYPES OF CELLS

There are two fundamentally different types of cells. These ae:

• The prokaryotic cell
• The eukaryotic cell

PROKARYOTIC CELLS

These are the type of cells which do not have true nucleus. Their nucleus material (DNA) lies free in a region known as nucleoid. Example: Bacteria.

 

diagram:a typical structure of a prokaryotic cell.

 

EUKARYOTIC CELLS

These are cells which possess true nucleus and nucleus material are found inside the nucleus surrounded by the two membranes, i.e nucleus envelope. Example: plant cell, animal cell.

CELLS AS SEEN WITH LIGHT MICROSCOPE

The cell could be described as a small unit of living protoplasm always surrounded by cell surface membrane and sometimes as in case of plants surrounded by non living cellwall of cellulose.

The most conspicuous structure in the cell is the nucleus which contains a deeply staining material known as chromatin (colored materials) this is the loosely coiled form of chromosomes. Chromosomes appear as the thread like structure just before the nucleus division. They contain DNA (genetic material) that controls the cell activities and can replicate itself so that the new cells can form.

The living material between the nucleus and the cell surface membrane is known as cytoplasm. Cytoplasm contains variety of cell organelles.

 

ULTRASTRUCTURE OF ANIMAL AND PLANT CELLS

Ultra structure of the cell is the fine structure of the cell as seen under electron microscope. In the cell, there are organelles which are suspended within an aqeuos medium and contained within plasmamembrane. The living material between the nucleus and the cell surface membrane know as cytoplasm.

The fluid that remains when all organelles are removed is referred as cytosol.

 

 

 

 

 

 

Differences between prokaryotic and eukaryotic cells

Prokaryotic cell	Eukaryotic cell
Nucleus material are not enclosed by nuclear membrane	Nucleus material are enclosed by nuclear membrane
Contains few organelles	Contains many organelles
No membrane bounded organelles such as; chloroplast and mitochondria	Has membrane bounded organelles
DNA is circular and lies free in cytoplasm	DNA is linear and enclosed in nucleus
No mitosis or meiosis, divide by binary fission	Mitosis and meiosis occur
It contains 70s ribosome (smaller)	It contains 80s ribosome (larger)
Mainly unicellular	Mainly multi-cellular

Note:

In unicellular organisms a single cell, perform all the life activities and characteristics of living organisms, the cell organelles work as organs in an organism.

 

CYTOLOGY

Is the study of cells structures and their functions

A cell is an organized independent mass of protoplasm (nucleus and cytoplasm) which makes the basic primary structure of an organism.

CELL CONCEPT:

One of the most important concept in biology is that a cell is a basic structural and functional unit of living organism.

This is known as a cell theory and was proposed jointly by two scientists . A Belgian Botanist called Schleiden and the German zoologist called Schwan. They studied the plant cell and animal cell respectively and come up with the idea that plants and animals are made up by small individuals which perform different functions of the whole organism. They finally come up with what they say cell theory.

The cell theory embraces four ideas, these are:

1. Living organisms are made up of smallest sufficient unit of living matter called cell.
2. The new cell is derived from pre-existing ones by cell division.
3. Each cell is independent with others but function as integral part of the whole organism.
4. The cell contains the hereditary material which is passed from generation to generation.

TYPES OF CELLS

There are two fundamentally different types of cells. These ae:

• The prokaryotic cell
• The eukaryotic cell

PROKARYOTIC CELLS

These are the type of cells which do not have true nucleus. Their nucleus material (DNA) lies free in a region known as nucleoid. Example: Bacteria.

 

diagram:a typical structure of a prokaryotic cell.

 

EUKARYOTIC CELLS

These are cells which possess true nucleus and nucleus material are found inside the nucleus surrounded by the two membranes, i.e nucleus envelope. Example: plant cell, animal cell.

CELLS AS SEEN WITH LIGHT MICROSCOPE

The cell could be described as a small unit of living protoplasm always surrounded by cell surface membrane and sometimes as in case of plants surrounded by non living cellwall of cellulose.

The most conspicuous structure in the cell is the nucleus which contains a deeply staining material known as chromatin (colored materials) this is the loosely coiled form of chromosomes. Chromosomes appear as the thread like structure just before the nucleus division. They contain DNA (genetic material) that controls the cell activities and can replicate itself so that the new cells can form.

The living material between the nucleus and the cell surface membrane is known as cytoplasm. Cytoplasm contains variety of cell organelles.

 

ULTRASTRUCTURE OF ANIMAL AND PLANT CELLS

Ultra structure of the cell is the fine structure of the cell as seen under electron microscope. In the cell, there are organelles which are suspended within an aqeuos medium and contained within plasmamembrane. The living material between the nucleus and the cell surface membrane know as cytoplasm.

The fluid that remains when all organelles are removed is referred as cytosol.

 

 

 

 

 

 

Differences between prokaryotic and eukaryotic cells

Prokaryotic cell	Eukaryotic cell
Nucleus material are not enclosed by nuclear membrane	Nucleus material are enclosed by nuclear membrane
Contains few organelles	Contains many organelles
No membrane bounded organelles such as; chloroplast and mitochondria	Has membrane bounded organelles
DNA is circular and lies free in cytoplasm	DNA is linear and enclosed in nucleus
No mitosis or meiosis, divide by binary fission	Mitosis and meiosis occur
It contains 70s ribosome (smaller)	It contains 80s ribosome (larger)
Mainly unicellular	Mainly multi-cellular

Note:

In unicellular organisms a single cell, perform all the life activities and characteristics of living organisms, the cell organelles work as organs in an organism.

 CYTOLOGY

Is the study of cells structures and their functions

A cell is an organized independent mass of protoplasm (nucleus and cytoplasm) which makes the basic primary structure of an organism.

CELL CONCEPT:

One of the most important concept in biology is that a cell is a basic structural and functional unit of living organism.

This is known as a cell theory and was proposed jointly by two scientists . A Belgian Botanist called Schleiden and the German zoologist called Schwan. They studied the plant cell and animal cell respectively and come up with the idea that plants and animals are made up by small individuals which perform different functions of the whole organism. They finally come up with what they say cell theory.

The cell theory embraces four ideas, these are:

1. Living organisms are made up of smallest sufficient unit of living matter called cell.
2. The new cell is derived from pre-existing ones by cell division.
3. Each cell is independent with others but function as integral part of the whole organism.
4. The cell contains the hereditary material which is passed from generation to generation.

TYPES OF CELLS

There are two fundamentally different types of cells. These ae:

• The prokaryotic cell
• The eukaryotic cell

PROKARYOTIC CELLS

These are the type of cells which do not have true nucleus. Their nucleus material (DNA) lies free in a region known as nucleoid. Example: Bacteria.

 

diagram:a typical structure of a prokaryotic cell.

 

EUKARYOTIC CELLS

These are cells which possess true nucleus and nucleus material are found inside the nucleus surrounded by the two membranes, i.e nucleus envelope. Example: plant cell, animal cell.

CELLS AS SEEN WITH LIGHT MICROSCOPE

The cell could be described as a small unit of living protoplasm always surrounded by cell surface membrane and sometimes as in case of plants surrounded by non living cellwall of cellulose.

The most conspicuous structure in the cell is the nucleus which contains a deeply staining material known as chromatin (colored materials) this is the loosely coiled form of chromosomes. Chromosomes appear as the thread like structure just before the nucleus division. They contain DNA (genetic material) that controls the cell activities and can replicate itself so that the new cells can form.

The living material between the nucleus and the cell surface membrane is known as cytoplasm. Cytoplasm contains variety of cell organelles.

 

ULTRASTRUCTURE OF ANIMAL AND PLANT CELLS

Ultra structure of the cell is the fine structure of the cell as seen under electron microscope. In the cell, there are organelles which are suspended within an aqeuos medium and contained within plasmamembrane. The living material between the nucleus and the cell surface membrane know as cytoplasm.

The fluid that remains when all organelles are removed is referred as cytosol.

 

 

 

 

 

 

Differences between prokaryotic and eukaryotic cells

Prokaryotic cell	Eukaryotic cell
Nucleus material are not enclosed by nuclear membrane	Nucleus material are enclosed by nuclear membrane
Contains few organelles	Contains many organelles
No membrane bounded organelles such as; chloroplast and mitochondria	Has membrane bounded organelles
DNA is circular and lies free in cytoplasm	DNA is linear and enclosed in nucleus
No mitosis or meiosis, divide by binary fission	Mitosis and meiosis occur
It contains 70s ribosome (smaller)	It contains 80s ribosome (larger)
Mainly unicellular	Mainly multi-cellular

Note:

In unicellular organisms a single cell, perform all the life activities and characteristics of living organisms, the cell organelles work as organs in an organism.

 CYTOLOGY

Is the study of cells structures and their functions

A cell is an organized independent mass of protoplasm (nucleus and cytoplasm) which makes the basic primary structure of an organism.

CELL CONCEPT:

One of the most important concept in biology is that a cell is a basic structural and functional unit of living organism.

This is known as a cell theory and was proposed jointly by two scientists . A Belgian Botanist called Schleiden and the German zoologist called Schwan. They studied the plant cell and animal cell respectively and come up with the idea that plants and animals are made up by small individuals which perform different functions of the whole organism. They finally come up with what they say cell theory.

The cell theory embraces four ideas, these are:

1. Living organisms are made up of smallest sufficient unit of living matter called cell.
2. The new cell is derived from pre-existing ones by cell division.
3. Each cell is independent with others but function as integral part of the whole organism.
4. The cell contains the hereditary material which is passed from generation to generation.

TYPES OF CELLS

There are two fundamentally different types of cells. These ae:

• The prokaryotic cell
• The eukaryotic cell

PROKARYOTIC CELLS

These are the type of cells which do not have true nucleus. Their nucleus material (DNA) lies free in a region known as nucleoid. Example: Bacteria.

 

diagram:a typical structure of a prokaryotic cell.

 

EUKARYOTIC CELLS

These are cells which possess true nucleus and nucleus material are found inside the nucleus surrounded by the two membranes, i.e nucleus envelope. Example: plant cell, animal cell.

CELLS AS SEEN WITH LIGHT MICROSCOPE

The cell could be described as a small unit of living protoplasm always surrounded by cell surface membrane and sometimes as in case of plants surrounded by non living cellwall of cellulose.

The most conspicuous structure in the cell is the nucleus which contains a deeply staining material known as chromatin (colored materials) this is the loosely coiled form of chromosomes. Chromosomes appear as the thread like structure just before the nucleus division. They contain DNA (genetic material) that controls the cell activities and can replicate itself so that the new cells can form.

The living material between the nucleus and the cell surface membrane is known as cytoplasm. Cytoplasm contains variety of cell organelles.

 

ULTRASTRUCTURE OF ANIMAL AND PLANT CELLS

Ultra structure of the cell is the fine structure of the cell as seen under electron microscope. In the cell, there are organelles which are suspended within an aqeuos medium and contained within plasmamembrane. The living material between the nucleus and the cell surface membrane know as cytoplasm.

The fluid that remains when all organelles are removed is referred as cytosol.

 

 

 

 

 

 

Differences between prokaryotic and eukaryotic cells

Prokaryotic cell	Eukaryotic cell
Nucleus material are not enclosed by nuclear membrane	Nucleus material are enclosed by nuclear membrane
Contains few organelles	Contains many organelles
No membrane bounded organelles such as; chloroplast and mitochondria	Has membrane bounded organelles
DNA is circular and lies free in cytoplasm	DNA is linear and enclosed in nucleus
No mitosis or meiosis, divide by binary fission	Mitosis and meiosis occur
It contains 70s ribosome (smaller)	It contains 80s ribosome (larger)
Mainly unicellular	Mainly multi-cellular

Note:

In unicellular organisms a single cell, perform all the life activities and characteristics of living organisms, the cell organelles work as organs in an organism.

 CYTOLOGY

Is the study of cells structures and their functions

A cell is an organized independent mass of protoplasm (nucleus and cytoplasm) which makes the basic primary structure of an organism.

CELL CONCEPT:

One of the most important concept in biology is that a cell is a basic structural and functional unit of living organism.

This is known as a cell theory and was proposed jointly by two scientists . A Belgian Botanist called Schleiden and the German zoologist called Schwan. They studied the plant cell and animal cell respectively and come up with the idea that plants and animals are made up by small individuals which perform different functions of the whole organism. They finally come up with what they say cell theory.

The cell theory embraces four ideas, these are:

1. Living organisms are made up of smallest sufficient unit of living matter called cell.
2. The new cell is derived from pre-existing ones by cell division.
3. Each cell is independent with others but function as integral part of the whole organism.
4. The cell contains the hereditary material which is passed from generation to generation.

TYPES OF CELLS

There are two fundamentally different types of cells. These ae:

• The prokaryotic cell
• The eukaryotic cell

PROKARYOTIC CELLS

These are the type of cells which do not have true nucleus. Their nucleus material (DNA) lies free in a region known as nucleoid. Example: Bacteria.

 

diagram:a typical structure of a prokaryotic cell.

 

EUKARYOTIC CELLS

These are cells which possess true nucleus and nucleus material are found inside the nucleus surrounded by the two membranes, i.e nucleus envelope. Example: plant cell, animal cell.

CELLS AS SEEN WITH LIGHT MICROSCOPE

The cell could be described as a small unit of living protoplasm always surrounded by cell surface membrane and sometimes as in case of plants surrounded by non living cellwall of cellulose.

The most conspicuous structure in the cell is the nucleus which contains a deeply staining material known as chromatin (colored materials) this is the loosely coiled form of chromosomes. Chromosomes appear as the thread like structure just before the nucleus division. They contain DNA (genetic material) that controls the cell activities and can replicate itself so that the new cells can form.

The living material between the nucleus and the cell surface membrane is known as cytoplasm. Cytoplasm contains variety of cell organelles.

 

ULTRASTRUCTURE OF ANIMAL AND PLANT CELLS

Ultra structure of the cell is the fine structure of the cell as seen under electron microscope. In the cell, there are organelles which are suspended within an aqeuos medium and contained within plasmamembrane. The living material between the nucleus and the cell surface membrane know as cytoplasm.

The fluid that remains when all organelles are removed is referred as cytosol.

 

 

 

 

 

 

Differences between prokaryotic and eukaryotic cells

Prokaryotic cell	Eukaryotic cell
Nucleus material are not enclosed by nuclear membrane	Nucleus material are enclosed by nuclear membrane
Contains few organelles	Contains many organelles
No membrane bounded organelles such as; chloroplast and mitochondria	Has membrane bounded organelles
DNA is circular and lies free in cytoplasm	DNA is linear and enclosed in nucleus
No mitosis or meiosis, divide by binary fission	Mitosis and meiosis occur
It contains 70s ribosome (smaller)	It contains 80s ribosome (larger)
Mainly unicellular	Mainly multi-cellular

Note:

In unicellular organisms a single cell, perform all the life activities and characteristics of living organisms, the cell organelles work as organs in an organism.

 

PAKUA FOMU KUJIUNGA KIDAO CHA TANO 2025